Abstract:ISD suspension has been widely studied by scholars，while semi-active control study on three components ISD suspension is still unsatisfactory. To study the influence of ISD semi-active suspension on automobile comfort and safety, a 2-DOF dynamic model for automobile ISD semi-active suspension was established. Simulation analysis adopted fuzzy control method with body vertical velocity and vertical acceleration signals as the fuzzy controller input was carried out on the suspension system. On this basis, a fuzzy control system for this suspension system was developed and designed by dSPACE, and its bench test was performed. The responses of ISD semi-active suspension to random road input at different velocity were analyzed. Simulation results were in agreement with experimental results. The results show that the mathematical model of ISD semi-active suspension is correct, and the ISD semi-active suspension with fuzzy control is superior to ISD suspension in damping suspension vibration as well as in improving vehicle running smoothness.

Abstract:Aiming to the problem of poor tractor performance, the matching bench test of positioning valve input voltage and magnetorheological damper excitation current was done. Based on the matching test, a frequency adjust based control strategy was proposed. Using LabView as the software development platform and PCI6024E DAQ as the core, the semi-active suspension control system was established and validated. The results showed that the reasonable match of positioning valve input voltage and magnetorheological damper excitation current could significantly attenuate the suspension dynamic characteristic response. The semi-active suspension control system could effectively suppress the sprung mass vertical vibration, and improve the tractor performance. 

Abstract:Based on particle swarm optimization (PSO) algorithm, a fuzzy self-tuning controller parameters optimization method was developed. With the co-simulation of Carsim and Simulink, typical optimized working conditions were selected. The controller’s scaling factor value and the position of membership function shape points were randomly selected to ensure the controller optimal performance. The controller was also reconstructed. Optimum remembering points and contrast mechanism among these points were working in PSO algorithm with the optimum target function. The actual vehicle experiments were carried out under typical working conditions. The experiment results showed that the optimized controller had good control performance, which could decrease the design workload of performance matching between the adaptive cruise control and test vehicle. 

Abstract:The combination of vehicle steering system and front suspension system is a dynamic coupled system. In allusion to coupled nonlinear vibration system of a car steering system and front suspension, a high dimension coupled 7-DOF. nonlinear vibration model was constructed using a concentrated parameters method. The nonlinear lateral force of tires, the nonlinear elastic force and damping force of the front suspension and the elastic effect of steering system connective poles were taken into account during the modeling. The dynamic characteristics of the coupled system and the parameter effects of automotive steering and front suspension were illustrated by numerical analysis when the mass unbalance existed in the front wheel, and the vibration relation between the steering system and front suspension was revealed. Research results can provide the theoretical support for dynamic design and synthetical dynamic control of coupled nonlinear vibration system.

Abstract:A damping multi-mode adaptive switching control mode was proposed. According to the actual vehicle driving condition and the performance characteristics of electronically controlled air suspension (ECAS), four damping control modes, such as high body height mode, middle body height mode, low body height mode and steering mode, were designed. The switching strategy between different modes was made by logical judgment. By using Simulink/Stateflow, the multi-mode adaptive switching control system was established, which could choose the optimum damping control mode according to the actual driving condition. Based on the control objectives of different control modes, the corresponding damping local controllers were designed to guarantee the local control quality of the system. The vehicle tests of the control system were carried out finally, and the effectiveness and availability of the control method proposed was verified by the experimental results.

Abstract:Considering the local head loss, the frictional head loss, rod padding effect and throttle orifice flow effect, shock absorber throttle formula after the valve opening were analyzed. Three contact types between valve disc and spring seat were investigated, which were circumference line contact, circumference surface contact with entirely hydraulic pressure subjection, and circumference surface contact with partially hydraulic pressure subjection. Corresponding valve disc deformation calculations were established based on the theory of shells and the finite element. The test of damping force vs velocity characteristic was finished, and the curve of pressure vs velocity characteristic at throttle was obtained. It verified the rationality of the transient fluid-structure interaction simulation (FSI). The distribution and the history of the valve disc deformation and the fluid field gained from FSI simulations coincided with Java numerical simulation from theoretic method.

Abstract:Based on the analysis of the structure and working principles of a ball piston vehicle steering pump, the dynamic characteristic equations of the new pump were set up from the force and flow balance. Then based on those equations, the corresponding simulations and experimental investigation were carried out. The results indicated that the output flow would decrease drastically when the rotation speed of the pump exceeded the opening speed of rotation, which met the requirements of the vehicle steering working condition.

Abstract:A virtual test system used to measure angular velocity on the top of driver seat was constructed based on CAN and TCP/IP bus. The program running in PC was designed based on LabVIEW, of which the status machine structure ensured the program to be easily read and maintained, and the queue structure increased efficiency of program implementing data sampling and processing in parallel. The system had the characteristics of high degree of integration, small size of sensors, convenient installation and function expansion on the spot. Four ride comfort regulations at home and abroad were comparatively analyzed and the test system constructed was used and verified in road way tests. The influence of angular velocity on the top of driver seat on evaluation index increased with the vehicle velocity, and it neared 20% (ISO standard) when the vehicle velocity reached 70km/h so that it could not be ignored. Additionally, the estimation method of acceleration PSD (power spectral density) and sampling frequency of original signal had a major impact on the evaluation index. Relatively speaking, the time domain method was more stable and reliable. However, it was difficult to determine the filter accorded with frequency domain weighting.

Abstract:In order to solve the problems of wheat no-till seeders in annual double cropping area of North China Plain such as large amount of straw-covering, stubble-bulky, residue-blocking, and bad passing capacity and planting quality, the new anti-blocking device using floated support was designed. This paper elaborated the working principle. Major working parts of the anti-blocking device were designed, and the structure parameters were determined. The field experiment showed that the no-till planter with floated support anti-blocking device had good passing capacity. Compare with strip-rotary anti-blocking device, floated support anti-blocking device reduced soil disturbance and oil consumption by 25% and 7.04% respectively.

Abstract:In order to improve the working performance of cassava harvester, multi-objective optimization design for the rack of the harvester was conducted. Under the CAD/CAE integrated design platforms, the statics finite element analysis and sensitivity analysis of the original rack were executed. Based on the above analysis, the multi-objective optimization design model for the rack was built, and six groups of non-inferior solution were obtained. From six groups of optimization design schemes and original design scheme, the optimal design scheme was selected by using fuzzy matter-element method and entropy-weight method. Comparative analysis on rack before and after optimization design showed that the rack’s mass reduced 4.29% and the maximum deformation reduced 27.04%, which proved that the proposed structural optimization design method for cassava harvester’s rack based on sensitivity analysis was reasonable and feasible.

Abstract:An auto-follow row mechanism was designed. A three-dimensional model of the auto-follow row mechanism was built under the application of UG, and then imported to the mechanical system dynamics simulation software ADAMS to build a virtual prototype model. Taking beet as harvest object, the simulation of the auto-follow row movement in ADAMS / View environment was conducted by setting the model parameters, adding constraints and drive. Taking the return spring stiffness, reset spring preload and operating forward speed of the auto-follow row mechanism as influencing factors, and taking the angular velocity of the angle sensor as the objective function to characterize auto-follow row sensitivity and drain digging rate, a virtual orthogonal test of parameters was performed, which affected auto-follow row movement. A field verification test was also carried out and the results showed that the effect of the return spring stiffness was not significant. When the return spring preload force was 200 N, the forward operating speed was 1.5 m/s, and the drain dug loss rate was minimum.

Abstract:A cylinder-type pneumatic centralized precision metering device for rapeseed was designed. The structural composition, operating parameters and working principle of metering device were analyzed. The single factor and orthogonal experiments were conducted. The rotational speed of seeding cylinder, positive pressure and negative pressure were used as the experiment factor. The bench experiments showed that the damage rate was below 0.5%. When the rotational speed of seeding cylinder was 20 r/min,the positive pressure and negative pressure was 2200 Pa and -2200 Pa, it was found that the quality index was 94.02%, the loss index was below 4.0%，and the variation coefficient of the consistency of each line displacement and stability of the total displacement were 5.73% and 1.21%, respectively. 

Abstract:A method to simultaneously tie double-α-knots by using two bill hooks was put forward. Driven by a toothed disk with a symmetric intermittent gearing and a cam groove, the two bill hooks of the double-α-knot knotter rotated intermittently in the opposite direction at an identical speed and the arm swung in accordance with the regularity of holding the strand, pushing the loop and cutting the strand. The transmission scheme to implement sequentially the holding of the strand, the cutting of the strand, the pushing of the loop and the return of the knotter by transforming the rotation of the cam to that of the oscillating of the arm was determined according to the demands of the baling. The curve equation of the cam profile was established by means of the kinematic inversion. A detailed curve of the cam profile was obtained by programming in Matlab and the force transfer characteristic was analyzed. A knotting test rig was developed. The results of simulating the baling process on the test rig indicated that rigorous synchronization of motion of the two α-knot knotters driven by the toothed disk and their corresponding force transfer met the requirements of the matching of the structure, the position and the motion of double-α-knot knotter.

Abstract:A flexible nozzle of the variable-rate sprinkler was developed. As the pressure increased, the diameter of the flexible nozzle increased and then the degree of fogging reduced. The main parameters of the nozzle, cone angle, range nozzle, length of end cylindrical section, thickness of elastic material, and extended volume of nozzle, were investigated. The 3-D solid model of the flexible variable nozzle and its internal runner were established using ANSYS software. The internal flow field of the flexible nozzle was simulated using computational fluid dynamics (CFD) software with k-ε model and ANSYS software with one-way fluid solid coupling model at different working pressure and different range nozzle. Relationship between working pressure, range nozzle and nozzle flow were evaluated. Simulation results were verified and precision of model was improved by measuring the displacement of the nozzle, the nozzle flow and the working pressure of the produced nozzle samples.

Abstract:This study used two high speed digital cameras to test and analyze the process and result of spray droplet impact on the soybean leaf surface. The result showed that when spray droplets were deposited and rebound broken, K values were less than 57.7. When splashing, K values of the most droplets were more than 57.7 because of the dense pilose of the leaf surface. The droplets were splashed easily at a low impact angle. K values were less than 57.7 when impact angles were 28° and 44°. Considering the same particle size and impact angle in the deposited droplets, the maximum spreading increased and the spreading time prolonged with increasing impact velocity. The final maximum spreading ratio of the high impact velocity was close to the low impact velocity. Deposit locations significantly influenced the process and result of the droplet spreading. In the process of receding break up, the droplets separated and were broken under the rebound action of the surface tension and viscosity of the leaf surface. Compared with the droplets deposited on the leaf surface, the total final maximum spreading ratio of the droplets enlarged greatly after receding break up. The total final maximum spreading ratio of uniform droplets was larger than that of nonuniform droplets. When Weber number (We) of the impact was high, the spray droplets appeared as a series of small droplets. When We was low, the spray droplets appeared as two to three large droplets. The final maximum spreading ratio of the main body of the droplets after spraying a series of small droplets was larger than that when individual large droplets are sprayed.

Abstract:The effects of two types of commercial pesticides on the rice quality were investigated under the low volume aerial application. It could provide guidance for the pesticide application and choose the right types of pesticides. For chlorpyrifos and hexaconazole pesticides, aerial and traditional spraying on Nangeng 5050 rice was used during the growing season. The differences of postharvest rice quality and also the kernel spectrum of DMA between aerial application in high concentration and low volume and traditional spraying were investigated. It was found that rice kernel hardness for aerial application with chlorpyrifos was higher than tradition spraying application but no significant difference with hexaconazole application. With X-ray diffraction analyzer, it was found that the effect of aerial application was smaller than traditional one for the microstructure of rice kernels.

Abstract:The measurement of soil infiltration has long been a great concern of scientific researches and applicants. Ring infiltrometeris a widely-applied instrument for soil infiltration measurement. Rain simulator and double ring methods are the common methods for measuring soil infiltration, but the disc infiltrometer is widely for determination of saturated hydraulic conductivity. Numerous reports indicated that the most reliable results measured by the ring infiltrometer in the saturated hydraulic conductivity. This indicates the drawbacks of the ring infiltrometer. The gaps between the ring and the soil during the ring being inserted into soil produces a passage for preferential flow to cause much higher infiltration rate. The relative long time interval between each measurement is another reason to produce higher measured infiltration rates, which is illustrated by numerical computational procedures. Both the time moment at which the computed infiltration rate is assigned to and the length of time step have their impacts on the measured soil infiltration curve. The errors caused by these factors, especially at the beginning of infiltration are illustrated. 

Abstract:A joint model of the temporal and spatial variation of soil properties was built, which integrated traditional statistics, spatial trend analysis, time stability assessment, and geostatistical hybrid model based on GIS. The joint model was used to reveal the spatio-temporal changes of soil organic matter and its influencing factors in Miyun County, Beijing. The results showed that the joint spatio-temporal model could preferably reflect the characteristics of soil organic matter（SOM）for high landscape heterogeneity in detail. SOM displayed medium time stability, and the random parts accounted for the spatial variability increased gradually. Patterns of spatial distribution of SOM content were consistent in different years. The SOM content in high value area gradually decreased over time, and increased in low value area. And the variation was large in high values range and small in low value area. The main factors impacting spatio-temporal variation of SOM were soil texture and land use in the study area. 

Abstract:Field plot experiment was carried out to investigate the effects of the powdered, ammoniated straw and/or blending with inorganic soil amendment (calcium sulfate) on soil moisture and crop yields in summer maize and winter wheat rotation systems. The results showed that the ammoniated straw could improve soil storage ability for precipitation, compared with CK1, and significantly increase the soil water storage (0~100 cm). The ammoniated straw improving soil water storage ability was observed mainly in seedling stage of summer maize and heading stage of winter wheat in the crops rotation spectively. Treatment, the powdered and ammoniated straw blended with calcium sulfate, compared with CK1, could significantly increase ecnomic yield of summer maize, winter wheat by 4.97% and 30.32%, respectively. The ammoniated straw returned to soil,compared with the unammoniated straw mulched soil, could distinctly increase yields of summer maize, winter wheat by 4.56%~10.00% and 6.65%~11.12%. 

Abstract:An experiment with two factors randomized block experimental design was conducted based on the evaporation of standard 20 cm pan to study the effect of different irrigation scheduling on salt distribution and salinity leaching in soil profile of cotton field with drip irrigation under plastic mulch. The results showed that to increase irrigation frequency and water amount was beneficial to soil salinity leaching in horizontal direction. The actual depths of soil salinity leaching for 5 d and 8 d frequency treatments were 0 to 20 cm and 0 to 30 cm respectively. As the soil depth increased, the soil salinity content for 5 d frequency treatment showed a first rising and then decreasing trend, while for the 8 d frequency treatment, it kept an approximately constant value in 0 to 100 cm soil profile. The soil salt content in 0 to 60 cm soil depth for medium water amount treatment (T60) was lower than that of high (T80) or low (T40) treatment. Compared with the soil salt content before sowing, the salt content in 0 to 20 cm soil layer at harvest time increased and decreased in 30 to 60 cm soil layer. The salt content within 0 to 60 cm soil layer showed an increasing trend as a whole. The salt content of medium water amount treatment (T60)showed a minimum variation, and the desalting rate was 0.44%. The irrigation scheduling had no significant effects on soil salt content in 0 to 100 cm soil layer. In addition, with the same irrigation frequency, applying high or low water amount was not beneficial to boll weight and yield improvement however. Combining high irrigation frequency（5 d） with medium water amount （T60） treatment acquired the highest seed cotton yield by9.18t/hm2, and it was regarded as the optimal irrigation scheduling for reasonable soil salt distribution, good salt leaching effect, higher yield and effective water application. 

Abstract:In order to research the characteristics of wetted soil under miostube-irrigation, five different buried depths and six different pressure heads were designed to investigate soil water movement through indoor soil box experiments. The results revealed that the pressure was the key factor to decide the miostube-irrigation flow, and the buried depths of miostube-belt had significant effect on the shape of wetted soil. The horizontal migration distance and ratio of width to depth of γ decreased with the increase of buried depths and vertical migration distance slightly increased with the increase of buried depths. There was a negative correlation between cumulative infiltration and buried depths and changing process of infiltration with irrigation time was accorded with Kostiakov infiltration model. The simulation model of cumulative infiltration under different buried depths was established and tested with measured values. The results showed that the experimental equation of infiltration had a high correlation coefficient between the measured value and the calculated value. There was a positive correlation between soil moisture uniformity and buried depth, and the suitable buried depths of clay loam of miostube irrigation were between 15 and 20 cm. 

Abstract:Based on the formula of flow deviation rate proposed by authors in reference [10], the further derivation was conducted to simplify the parameters in the formula for designing drip irrigation system economically and credibly. According to the hydraulic analysis using step-by-step method, the integrated flow deviation rates for a drip irrigation submain unit were calculated at different emitter manufacturing variation. The formula of flow deviation rate was verified by the statistical analysis of the integrated flow deviation rate. Further, the effect of emitter manufacturing variation on integrated flow deviation rate was analyzed using the formula, and the allowable value for integrated flow deviation rate of drip irrigation submain unit was recommended for drip irrigation system design.

Abstract:In order to quantify ground temperature and light distribution under furrow irrigation, a model of ground temperature and light transmission was developed, and changes of ground solar radiation and temperature in different positions of maize field with furrow irrigation were simulated. The model was based on the geometrical-physical relationship between ground surface structure and incident light, taking crops coverage into account under alternate furrow irrigation and conventional furrow irrigation. The results showed that the surface solar radiation and surface temperature at dry sites was higher than that at wet sites, and the difference changed among maize growing stage. At the same time, mean value of the surface solar radiation under alternative furrow irrigation was higher than that under conventional furrow irrigation by 18.64~30.60 W/m2, difference in the surface temperature was 0.38~3.00℃. the absolute deviation between the simulated and measured values of solar radiation in different sits of soil surface under different furrow irrigation methods was 0.23~24.89 W/m2, the MAE 3.36~13.79, the RMSE 4.90~13.51, the di 0.93~0.99; the absolute deviation between the simulated and measured values of soil temperature of soil surface was 0.1~1.7℃, the MAE 0.07~1.11, the RMSE 0.16~0.93, the di greater than 0.94. Therefore, changes of solar radiation and soil temperature in soil surface of furrow and ridge could be simulated by the model of ground temperature and light distribution with reasonable accuracy.

Abstract:This article presented a method for direct measurement of soil moisture, which was equivalent to the conventional oven-dry method. Under assumed soil particle density, soil samples for measurement were placed into a container of known volume, and then the container was filled with water to saturated. The weights before and after saturation of the soil sample, the assumed soil particle density and water density, were used to estimate the original soil moisture content. The measurement method, procedures as well as the computational method and procedures were detailed. Four soils were used for the validation experiments, under five initial soil water contents 10%, 15%, 20%, 25% and 30%. The measured results were compared with those measured by the oven-dry method. The data showed that the measured moisture contents by the new method were about 2.4%~2.7% higher than those by the traditional method after oven-dry for 8 h. Extended oven-dry for 12 to 48 h produced 1%~3% higher water content than dried for 8 h. The proposed method performs better than the conventional method. The results indicate the feasibility of the new method. 

Abstract:The previous retrieval models of soil moisture based on active microwave remote sensing are applicable for non-periodic random surfaces, not available to periodic surfaces with row structure yet. This study was based on fully polarimetric data and field data. It was found that the like-polarized (hh and vv) backscattering coefficients react obviously to the azimuth angles, up to 4 dB. while the cross-polarized (vh) backscattering reacts insensitively to row-direction changes, then the response functions of hh and vv polarizations were given. A distance parameter that denotes the distance between a sampling point and response function curve was constructed to remove the influence of azimuth angles. The correlation coefficients between the distance parameter and soil moisture were 0.7095 and 0.8723, in hh and vv polarization modes, respectively. Meanwhile the influence of the error of roughness parameters in field measurement was removed by three different polarization combination schemes. The effectiveness of this model was demonstrated by the estimated soil moisture of checkpoints. This study selected 18 sampling points as checkpoints.The correlation coefficient between estimated soil moisture and measured soil moisture was up to 0.9461, the standard deviation was 0.0366 cm3/cm3. The model was reliable and applicable for periodic surfaces.

Abstract:Biomass pyrolysis is a high value-added process of biomass conversion. The direct pyrolysis experiments of no crushed cotton stalks were conducted. The results showed that the solid product and fixed carbon (FC) content were maximum when pyrolysis temperature was in 400℃. As the pyrolysis reaction proceeded, the higher temperature increased and the solid products reduced, and the ash content in the products increased accordingly, which led to a decrease in fixed carbon (FC) content after 400℃. In order to determine the optimum technological parameter of pyrolysis, an orthogonal experiment was conducted.The maximum product yield of 49.98% was obtained with 5℃/min of heating rates, 400℃ of optimum pyrolysis temperature, and 2h of holding time.

Abstract:Taking the mixture of vegetable wastes and cow manure as the raw materials and using aerobic fermentation process for fermentation tests, the experiment was conducted and optimized to analyze the effects of the ratio of raw materials, aeration time and fermentation time on the solid residues of vegetables. The pH value of fermentation liquid was real-time monitored and the TKN, NH+4-N, NO-3-N, NO-2-N and TP of 9 treatments were measured after optimized. Then the nutrient contents of fermentation liquid were investigated. Through the comprehensive range analysis and principal components analysis of 9 treatments, the optimal fermentation results were obtained with 3∶1 raw materials (mass ratio), 2 h/d aeration time and 40 d fermentation time.

Abstract:Magnetic resonance imaging (MRI) technology and artificial neural network theory were used to discriminate the browning disease inside the fruit. Areas corresponding to the core of fragrant pear in T2-weighted image were selected to the region of interest (ROI). Quantitative analysis of the ROI was achieved by extracting ten texture features that reflected the browning characteristics. Back propagation (BP) neural network was carried out on the statistical features to predict the internal browning of fragrant pear. Genetic algorithm (GA) was adopted to optimize the initial weights and threshold in BP neural network. For four groups of samples, the optimization model showed 92.50% accuracy in detecting the presence of browning in fragrant pear, compared with the correct recognition rate 80.83% of the non-optimization, an 11.67 percent increased. For the same group samples, the recognition results of optimized model were also better than the non-optimized model and the correct recognition rate of each group was improved to varying degrees. The result of our experiment shows that the optimized model has good predictive accuracy and generalization ability to identify the internal browning of fragrant pear. 

Abstract:This experiment was conducted on Chardonnay dry white wines from five districts of China. In order to discriminate the different wines in terms of geographical origins, a visualization method was proposed to mining the chemical information of aromatic data. Solid-phase micro-extraction (SPME) followed by GC-MS technique was used to qualify and quantify volatile compounds in sample wines, and odor active values (OAV) of analytes were calculated and redefined. By the algorithm of gray-scale maps, the standardized data matrices were translated into visual aroma fingerprints of sample wines. The results showed that the gray scale maps corresponding to redefined OAV were better to distinguish Chardonnay dry white wines from different regions visually and easily.

Abstract:This work aimed to determine the anthocyanin content in skin based on hyperspectral imaging technology. The grapes of Cabernet Sauvignon (Vitis vinifera L.) produced in Shaanxi province were used as experimental materials. Hyperspectral images of 60 groups of grape samples were collected by near infrared hyperspectral camera (900~1700nm). After then, the anthocyanin content of skin was detected by pH-differential method. The grape berry regions of hyperspectral images were extracted as region of interest (ROI) in which its average spectrum was calculated. Moreover, different preprocessing methods were used to improve the signal noise ratio (SNR) including Savitzky-Golay smoothing, normalization and multiplicative scatter correction, et al. Prediction model was established for determining anthocyanin content by the partial least squares regression (PLSR), least squares support vector regression (SVR) and BP neural network (BPNN). It was shown that prediction coefficient of determination (P-R2) of BPNN model built by the thirteen latent variables recommended by PLSR model was 0.9102 and the root mean square error of prediction (RMSEP) was 0.3795. 

Abstract:Air samples were taken from an apple granary in order to find aroma-producing yeasts for cider fermentation. After performing separation, purification and ester production tests, six yeasts were obtained, which showed ester producing abilities. The colony morphology, cell morphology, liquid cultural characteristics, physiological and biochemical characteristics and ITS complete sequences of the six tested yeasts were analyzed. The six yeast stains were identified by sequence homology comparison with known sequences in GenBank and by constructing phylogenetic tree. Among the six yeasts, the strain YN6 identified as Wickerhamomyces anomalus, had the strongest aroma-producing ability，and could improve the sensory quality of cider. The results of GC-MS showed that, the cider the amounts of volatile compounds in the cider fermented by control cider yeast WLS21 was 248.09mg/L. But when mixed with YN6, the volatile compounds increased to 496.14mg/L.

Abstract:A microwave irradiation technique was applied for degradation of aflatoxin B1(AFB1) in corn flour, and immunoaffinity column clean-high performance liquid chromatography-post-column derivatization method was applied to determine the content of AFB1. The effects of microwave power, irradiation time and initial quality of AFB1 on degradation efficiency were investigated. Microwave irradiation was compared with conventional heating method. The results showed that the degradation of AFB1 was performed by non-thermal effect. The optimized microwave power was 250 W and irradiation time was 30 min. Under this condition, the degradation rate would reach to 90%. The residues of AFB1 were in the safety limit range of the national standard and the European Union. The nutrition quality of corn flour was slightly affected by the microwave irradiation treatment. The toxicity of AFB1 was reduced obviously and there was no secondary pollution. Therefore, the microwave irradiation can be used as an effective method for the degradation of AFB1. 

Abstract:The Catalase（CAT）, Peroxidase（POD）, Superoxide dismutase（SOD）, Polyphenol oxidase（PPO）and Phenylalnine ammonialyase（PAL）activity, the Superoxide anion free radical（O-2）generation rate, the Hydrogen peroxide（H2O2）, Salicylic acid and Lignin content of mung bean germinations were detected, which were subjected to different centrifugal intensity (acceleration), such as reversible damage(94g）, slight damage(376g）, moderate damage(845g）, serious damage(1503g）, and breakage damage(3381g）. One gravitational acceleration （g）=9.8m/s2. The results showed that the disease resistance would be induced by all the centrifugal damages including reversible damage in the early stage. The content of free Salicylic acid（SA） and H2O2, POD activity were significantly increased by reversible damage while the change of the O-2 generation rate, total hydroxybenzene, lignin content, the SOD, CAT, PAL and PPO activity were indistinctive. The significant changes of more disease resistance indicators were caused by slight damage, moderate damage and serious damage. Especially the POD activity was increased remarkably under slight damage and moderate damage. The content of free SA, H2O2, total hydroxybenzene and lignin rose in the maximum while the O-2 generation rate, the CAT, PAL and PPO activity declined in the maximum when it was treated with breakage damage. Besides, the SOD activity was not sensitive to all the damages. 

Abstract:To achieve the deep informationization in ginger industry chain, an information perception system was built based on the internet of things. By making full use of the concepts and methods of thorough perception, some information collection terminals were designed for different stages of ginger industry chain, such as planting stage perceived terminal, warehousing stage perceived terminal, processing stage perceived terminal, cold chain transport stage and sales stage perceived terminal, etc. And the information of the ginger industry chain was acquired automatically with these terminals. In order to achieve real-time query and information submission, a general information collection instrument for ginger industry chain was developed. Moreover, an industrial chain information management platform was developed with J2EE architecture, which could be managed effectively. The result of long-running shows that the system could acquire information comprehensively and accurately, and the system was stable and reliable.

Abstract:Based on self-developed measuring equipment, a method for measuring the reflection spectrum of crop canopy using active light source was discussed. As well as systematically introduced the measuring principle, five functional modules of the system were introduced. They were high-frequency modulated light source module, first-level amplifier circuit module of the photoelectric cell response, high pass filter module, second-level amplifier circuit module and signal extraction module. Theoretical analysis and derivation on the design of the two key parts, the first-level amplifier circuit module and the signal extraction module, were provided. Furthermore, the self-developed experimental equipment was used to measure the reflection spectrum in wheat field. The experimental results showed that the impact from passive light source on the measuring results was almost completely filtered, while the response caused by active light source was detected efficiently. Experimental results were stable and had a small fluctuation ratio of less than 4.97% during experiments.

Abstract:A clonal selection clustering algorithm was proposed to solve classification problem of the slope produced by the linear trend analysis. The experimental results showed that the DBI value of 065 was significantly less than the compared three algorithms. The result of vegetation change trend was in accord with the statistic data of greenbelt for everyone and green coverage percentage in Beijing from 1998 to 2011. So the proposed method had some application value and could widely apply in long time series of vegetation change trend analysis.

Abstract:A multispectral and panchromatic image fusion algorithm based on mean-shift segmentation and the non-subsampled shearlet transform (NSST) was presented. Mean-shift segmentation was performed on the panchromatic image, and the variance of each region was used to distinguish the multispectral image into regions that need to be spatially enhanced or not. Then, the multi-scale NSST was performed on the panchromatic image and the intensity component of the multispectral image. The low frequency components were fused based on the fourth-order correlation coefficient, and the band-pass frequency components were fused based on the variances of the segmented regions. At last, the fused intensity component was obtained by reconstruction of those fused components, and the inverse IHS transform was performed to obtain the fused high resolution multispectral image. Experimental results indicated that the proposed image fusion method could keep a balance between spectral preservation and spatial enhancement.

Abstract:The apple images were hard to be identified at a faster speed and a higher accuracy because of fuzzy and uncertain factors existing in the color image boundary pixels, so in order to overcome the disadvantages above, a model combined quantum genetic algorithm and fuzzy neural network was built up which showed the capability of global search capability and adaptation. In the proposed model, quantum genetic algorithm was used to optimize the initial value of adjustable parameter in fuzzy neural network, which avoided redundant iteration and the incline to fall into the local minimum value of traditional BP algorithm. The experimental results showed that the proposed model achieved accuracy of 100% for the uneven color samples, 96.86% for sunlight influenced samples, 94.29% for the adjacent samples, and 92.31% for the overlapping samples.

Abstract:Fresh tea leaf and stem separation for coarse tea not only improves the quality of finished tea, but also reduces heat energy consumption. To realize the separation, the key issue is the recognition of tea stems and petioles. Tilted chute was used to constrain the direction of fresh tea. Then, the problem was transformed into determining whether the tea sprout was facing up or down. At first, according to the stem end length, fresh tea was classified into two categories: for those with long stem ends, an algorithm based on the feature size was proposed, and the side with longer feature size was recognized as tea sprout. For those with short stem ends, the “local extreme points of fresh tea contour” was utilized, and the side with more local extreme points was recognized as tea sprout. Then, 168 randomly obtained images and a background image was used to validate the algorithm, and a recognition rate of 93.3% was reached. The average time to recognize the direction of a single fresh tea was 17.8 ms which fulfilled the requirements of real-time processing.

Abstract:In order to satisfy the safety and normal operation for intelligent agricultural vehicle, a method of detecting moving obstacles was proposed based on panoramic vision. Compared with the traditional monocular and binocular vision, panoramic vision possessed the advantages of 360° non-blind area detection. Firstly, multi-thread technology was used to acquire multi-vision images. The improved RANSAC-SIFT algorithm was used to extract and match feature points, and then stitch panoramic images. Secondly, improved CLG optical flow algorithm was used to detect moving obstacles based on panoramic images. Compared with the traditional SIFT algorithm , experiments showed that the accuracy of feature points matching was increased by 25.6% and the arithmetic speed was increased by 25.0%. Moving obstacle detection using improved CLG optical flow algorithm could take averagely 1.55 s to detect moving obstacles, and the accuracy was 95.0%.

Abstract:The control of agricultural vehicle traveling speed is an important factor of navigation system and variable rate application system in precision agriculture. The traveling speed control algorithm of agricultural vehicle in the field requires a higher adaptive ability because of adverse circumstance. The rice transplanter speed control system was designed on the basis of the analysis of vehicle speed shifting mechanism. The variable universe adaptive fuzzy PID (VFPID) control method was introduced to improve the adaptability of the control algorithm. The road test of control system was accomplished on the platform of rice transplanter. The test results showed that the average error was less than 0.02m/s and the control method was feasible and effective. As compared with PID results, the traveling speed stabilized in a short period for the VFPID control method, and the control method was more adaptive with the changes of set point and engine speed. 

Abstract:Frost protection effect experiments in tea fields were conducted according to wind machine operation timing on different time scales. The treatments of starting to use wind machines before tea sprouting, starting before frost occurrence and stopping after sunrise were set up respectively. And the impact of wind machine operation on the growth of tea trees, temperature rise in the canopy and protection coverage was measured. The results indicated that starting to use wind machines 20 d, 15 d and 7 d before tea sprouting increased the length of young shoot, bud density and 100-bud weight by over 20% compared with the control test; Starting wind machines 2.0 h, 1.5 h and 1.0 h before frost occurrenceled to better protection and enlarged the coverage radius by more than 60% compared with the control test. Delayed stopping of wind machines by 2.0 h, 1.5 h and 1.0 h after sunrise reduced the temperature rise of the canopy by 45.76% in the first hour, and narrowed the reduction of the photosynthetic intensity of tea leaves. Therefore, to protect tea trees from late frost cold for better growth and yield, the appropriate application of wind machines should be more than 7 d prior to the tea budding, and the operation timing of starting and stopping for a certain frost event should be 1.0 h before frost occurrence and 1.0 h after sunrise, respectively.

Abstract:Since environmental information in greenhouse had the characteristics of slow changing, great redundancy, and strong spatial and temporal correlation, a energy transmission model of wireless sensor network (WSN) was proposed based on event-driven and data fusion for the acquisition of environmental information in greenhouse. With the energy transmission model the field test was conducted. The results showed that the data transmission model based on event-driven could reduce the data transmission frequency 83.8%. The data fusion based on data support function could calculate each weighted value of the original data size according to the degree of association among the data, and was better than the arithmetic mean.

Abstract:The WSN technology used in greenhouse facilities cannot get rid of the situation of human monitoring, so the WSAN technology was proposed to be applied in greenhouse facilities. A cooperative mechanism of actors in WSAN applied in greenhouse facilities was discussed, which consisted of a redeployment algorithm of actor (RDAA) and a real-time tasks assignment algorithm based on the sealed first price auction (RTAA-SFPA). The RDAA algorithm was used to deploy the actors in the middle of the event region to achieve real-time response of the occurred events. RTAA-SFPA algorithm was used to take the occurred events as the tasks being assigned by method of sealed first price auction. The simulation results showed that the cooperative mechanism proposed had better performance on the assignment and solution of the tasks through actors cooperation for greenhouse facilities.

Abstract:In order to determine the installation parameters of mixing fans in open dairy cow house, field experiment was conducted to measure airflows in dairy cow house in Tianjin. After establishing 16 geometric model with different installation parameters of mixing fans，3-D steady simulation of airflow distributions was carried out in cow house. The effect of air flow disturbances was analyzed with fans installation height and tilt angle as influence factors and the ratio of the area where air velocity more than 1.0 m/s to total region in two surfaces which above the ground 1.0 m and 1.5 m as evaluation indexes. The result showed that there was no significant difference on effect of air flow disturbance between different installation height（P＞0.05）in the same tilt angle. The optimal tilt angles of fans were that fans over the cow bed of 20° and fans over the head gate assembly of 10°.

Abstract:In order to obtain the boundary feature of unorganized points, a method of boundary feature recognition and abstraction was proposed based on the kernel density estimation on k-neighborhood of every sample point. k-neighborhood of a sample point could be acquired quickly based on R*-tree index, and the radius of query area viewed as bandwidth was used to kernel density estimation on the point set consisted of the sample point and its k-neighborhood. In this way, the mode points reflected the distribution of point sets could be obtained. According to the ratio of distance between mode points and sample points to the bandwidh of kernel density estimation, the sample points located on boundary could be recognited and abstracted. The experimental results show that the algorithm can obtain the boundary feature of the unorganized points in uniform or nonuniform distribution exactly and rapidly. 

Abstract:For improving the diversity of existing multi-objective particle swarm optimization algorithm and keeping the balance between exploration and exploitation well, a multi-objective cellular PSO was proposed. The algorithm combined the concept of cellular automata with the multi-objective PSO theory. In addition, the relationship between the particles and the information transmission mechanism was studied, and a particle flight speed control strategy was presented. The results indicate that the improved algorithm outperforms the four compared algorithms concerning the convergence and diversity in solving multi-objective optimization problems with unconstraint and constraint. And also, the new algorithm can get more accurate solutions when applied in disc brake design problem.

Abstract:A novel bionic joint spherical metamorphic mechanism was analyzed. It consisted of a base platform, moving platform, three circle legs and one middle metamorphic leg had two configurations named configuration 1 (normal configuration) and configuration 2 (metamorphic configuration). The metamorphic mechanism can transform normal configuration to metamorphic configuration with the change of middle leg. Firstly, kinematic equation was established, and the solutions to inverse kinematic and velocity Jacobian matrix were given. Then the relationship between workspace and links length was discussed based on inverse kinematic solutions. According to regular pattern, the workspace of the mechanism was optimized and the default workspace was determined. Finally, the optimization of links length was given based on the evaluation of payload capacity index and stiffness index for a prescribed workspace. The size ranges of links were respectively obtained when each performance index at a better level. The best design size of the mechanism was obtained based on the comprehensive two indexes.

Abstract:Gaussian distribution was used to describe the rough surface, and a novel method was proposed to generate 3-D rectangular rough microchannel by using Coons surfaces. With this method, one smooth microchannel and three rough microchannels were created. Constant wall temperature condition was applied to simulate the laminar flow of the saturated water in microchannels, and the effects of the surface roughness on flow and heat transfer characteristics were all investigated. The results indicated that different from the smooth microchannel, Poiseuille number and average Nusselt number were larger than the theoretical values, and increase approximately linearly with Re. As the height of the surface profile changed randomly, both pressure drop and local Nusselt number along the channel fluctuated randomly. The larger the roughness was, the more intense the fluctuation was. Poiseuille number and average Nusselt number increased with increasing equivalent relative roughness. Furthermore, within the scope of the Re, the effect of relative roughness on laminar heat transfer was stronger than that on flow resistance. In the microchannel, isotherm migrated to the lower surface, where the roughness was larger. As a result, the temperature distribution was asymmetric. As the gap of the roughness got increasingly larger, the asymmetry was more and more distinct.

Abstract:In order to study the electromechanical coupling characteristic of dielectric electroactive polymer, the force analysis of DEAP under electrical field was performed, and the nonlinear electromechanical constitutive model was presented by combing the hyperelastic theory. On the basis of the model, the mechanical behavior of circular actuator was discussed. The Yeoh form of DEAP constitutive equation, the equilibrium equations and the boundary conditions were given. Thus, the principal stretch ratio and principal stress in the membrane of DEAP actuator were obtained by solving the differential equations. At the same time, the influences of pre-stretch ratio, the area of active region and actuation voltages on deformation of actuator were analyzed. And the experimental results for deformation behavior of circular DEAP actuator under voltage actuation were consistent with the theoretical analysis results. It was found that the optimal pre-stretch ratio was 3～4. 

Abstract:Taking low speed high torque water hydraulic motor as the main research object, the movement of port plate, rotor and piston were simulated by the dynamic mesh technique and UDF (user defined function) in Fluent．And 3-D internal flow field of water hydraulic motor and the model with damping groove were computed numerically. Based on the minimum through-flow area equation and the formula of pressure change, the mathematical model of the pressure of plunger cavity was established at various percolation angles. The research showed that the original model of plunger cavity had significant pressure overshoot, pressure oscillation, pressure surge, and velocity jump. When the model was modified, the internal flow field of plunger cavity became more stable, so that the shock in valve port process could be effectively reduced and the phenomenon of pressure rise was reduced and the oscillation amplitude and time were decreased. The aim of pre-loading were well achieved. It was also found that the larger the percolation angle of damping groove was, the more effective the pre-loading was. The research could be an important reference for port plate optimal design.

Abstract:The hollow hydraulic motor is a key assembly unit for inner frame driving of multi-axis huge inertia motion flight simulator. However the large friction caused by its special structure seriously influences the tracking performance and positioning precision of the servo system especially at very low velocity. A mathematical model of the valve-based hollow hydraulic motor servo system was established. The friction state observer was proposed based on the LuGre dynamic friction model. On this basis, the sliding mode variable structure control algorithm with friction state observer was developed to compensate the friction torque, and the experiment was carried out. The result shows that the proposed state observer can estimate the friction torque correctly, and compared to that without observer, the sliding mode controller with observer can get more precise trajectory tracking. 

Abstract:By means of experiments, the damping characteristics of the cast iron ground surfaces in contact normal was studied. It was found that the formulation of complex damping was a better representation of the test results and rules than the formulation of complex stiffness. Firstly, the relationship between contact pressure and deformation contact layer subjected to a harmonic excitation was studied and the complex damping method was used to establish the contact dynamic equation of steady state. The phase that normal contact deformation lags behind exciting force was used to reflect contact damping. Secondly, effect of normal pre-loaded pressure, amplitude of exciting force, and exciting frequency on the lagging phase were investigated. The results showed that the phase varies between 1.5° and 55° when pre-loaded pressure was from 0.205 MPa to 1.68 MPa, and amplitude of exciting force was from 22.7 kPa to 296 kPa and exciting frequency was from 0.25 Hz to 128 Hz. The relationship between the phase and pre load pressure was linear, and with pre-loaded pressure increased, the phase decreased. The relationship between the phase and exciting frequency was almost linear when exciting frequency was relatively high, and with frequency increased, the phase increased. It was also found that the relationship between the phase and amplitude of exciting force was non-monotonic. When the amplitude of exciting force was relatively small, the phase had a maximum value. In other words, only under modest amplitude of exciting force, the contact damping had a maximum value. 

Abstract:The error kinematics mathematic model of 6-DOF robot and 2-DOF positioner was established on the basis of differential transformation matrix. When robot was machining, the dynamic error and the static error were coupling. The relationship between two adjacent rod of the dynamic error and the static error was analyzed on the perturbation method, and then the relationship of dynamic error and the static error between robot end effector and each joint was built. Based on the perturbation method, the synthesis error compensation model was created by decoupling the dynamic error and the static error， and then the effectivity of the compensation model was proved. The compensation value of each robot joint can be obtained from the model.